Y chromosome linked to cow infertility

In the cattle industry calf production in female cows is one of the most important traits producers are looking for in terms of economic stability in their herds. If a cow cannot produce an offspring, farmers can see a significant reduction in annual revenue as costs associated with feed and labor continue to add up only to find the cow is unable to reproduce.

However, new research is showing that in a group of female cows studied, traces of the male Y chromosome are showing up only in the DNA of the animals that have failed to get pregnant. By knowing this early in a cow’s life, farmers could decide what animals are most beneficial to invest in.

According to a recent article, these original findings were discovered at the Agricultural Research Service’s Roman L. Hruska U.S. Meat Animal Research Center (USMARC) in Clay Center, Nebraska, where scientists examined records of 6,400 female cows from herds in Florida, Nebraska, Colorado, and at USMARC. The records indicated whether cows became pregnant in their first spring breeding and used “DNA pooling,” which combines DNA from individual animals into a single pool, to genotype the animals.

Following these compelling results, Neogen is offering Y chromosome results as an add on to its beef and dairy heifer genomic profiles which add to the extensive list of performance and disease traits that are available from a single DNA sample from a calf. Determining the existence of Y chromosome fragments in a heifer’s DNA can lead to better heifer replacement decisions, both for beef and dairy herds.

Typically, females inherit an X chromosome from each parent (XX) and males inherit an X and a Y (XY). Considering all the animals involved in the study were female, there should not have been any Y chromosome in their DNA, explained geneticist Tara McDaneld, who led the research.

According to the article, McDaneld and her team are further examining data from heifer populations for other variations in the genome and are finding other regions that may generate reproductive markers in the future. For example, they have identified a deletion on chromosome 5 that is associated with females’ inability to get pregnant, which they plan to pursue in further research.

“Producing calves to sell at the market every year is the main driver for beef cow producers,” said geneticist Larry Kuehn, who was involved with the research. “Heifers that conceive in their first calving season and then produce a calf every year thereafter are most profitable.”